it is doubtful whether these programs have any lasting effect
Not established as genuine or acceptable
of doubtful legality
open to doubt or suspicion; "the candidate's doubtful past"; "he has a dubious record indeed"; "what one found uncertain the other found dubious or downright false"; "it was more than dubitable whether the friend was as influential as she thought"- Karen Horney
fraught with uncertainty or doubt; "they were doubtful that the cord would hold"; "it was doubtful whether she would be admitted"; "dubious about agreeing to go"
unsettled in mind or opinion; "drew a few tentative conclusions"
(doubtfully) in a doubtful manner; "Gerald shook his head doubtfully"
(doubtfulness) doubt: the state of being unsure of something
Doubt, a status between belief and , involves uncertainty or distrust or lack of sureness of an alleged fact, an action, a motive, or a decision. ...
Subject to, or causing doubt; Experiencing or showing doubt; Undecided or of uncertain outcome; Fearsome, dreadful; Improbable or unlikely; Suspicious, or of dubious character; Unclear or unreliable
(DOUBTFULS) indigenous personnel who cannot be categorized as either Vietcong or civil offenders; suspect personnel spotted from ground or aircraft
(doubtfuls) locals who, after being questioned, can not be classified as either Viet Cong, civil offenders, or friendlies.
A loan that has all the weaknesses of a substandard loan plus it is difficult to collect in full.
double quantum transition for finding unresolved lines